I'm not sure what you meant, but I'll comment that Lifetime Warranties have less than zero to do with the accuracy of torque wrenches.
My guess is that 99.9 % of the click torque wrenches that rest in tool boxes are used by people that are 100% trusting of the wrench setting while having zero evidence of the device's accuracy.
I finally got around to buying the Proto J6006C I've had on my "get list" for some months now.
It's categorized as a ASME B107.14M-1994 wrench, meaning +/- 3 % accuracy of reading for 20 to 100 % of scale in the clockwise direction. It's a 80 ft/lb limit wrench, so the range of accuracy is from 16 to 80. The wrench goes down to 10, but that's a waste, and what a danger, as it's outside the accuracy band.
Each torque wrench is serial numbered and comes with a hand noted test card.
VERY INTERESTING TEST RESULTS for what is only supposed to be a 3 % accuracy torque wrench.
@ 20 % ,accuracy was only out by a factor of 1.0019
@ 60 % , accuracy was only out by a factor of 1.0104
@ 100%, accuracy was only out by a factor of 1.0063
So when one converts the factors to percent error, they are but a fraction of the allowable 3 %.
Interestingly enough, the Counterclockwise accuracy was way lower than 6 % through the full range, never more than 3 %.
Short story, a very accurate torque wrench for the price. (I paid regular price 185 CDN before tax @ KMS Tools)
The J6 range covers a broad range of ratings from low to high.
Good instructions as well.
Don't laugh at that.
It's mind boggling how many don't realize that A) storing a click type torque wrench that has not be zeroed out to its minimum results in bogus readings the next time you use it, and B) for maximum accuracy, set the wrench to it's limit, and take it to "click" at least 3 times before you start using it - particularly for wrenches used infrequently.